1. Field of the Invention
The present invention relates to a data transmitting apparatus, a data receiving apparatus, a data transmitting method, and a data receiving method. More particularly, the present invention relates to a data transmitting apparatus, a data receiving apparatus, a data transmitting method, and a data receiving method that verify the validity of a device in wireless communication.
2. Description of the Related Art
In related art, for the purpose of protecting the copyright of music content, video content, etc., various protocols, e.g., HDMI (High-Definition Multimedia Interface), are proposed. For a content protection scheme, for example, HDCP (High-bandwidth Digital Content Protection system) is used. The HDCP standard defines a key sharing scheme for device authentication or authentication between the transmitting side and the receiving side, an encryption scheme for content to be transmitted, etc.
In authentication based on the HDCP standard, etc., a device key for individually authenticating a communication partner's apparatus by public key encryption is used. When authentication between a transmitting apparatus and a receiving apparatus succeeds, the transmitting apparatus encrypts a video signal using a device key and transmits the encrypted video signal and the receiving apparatus decrypts the received video signal using a device key.
Also, in the HDCP standard, the above-described authentication process is performed and a so-called revocation process for determining whether the receiving apparatus is an unauthorized device is performed. Only after the receiving apparatus is determined by the revocation process not to be an unauthorized device, encryption transmission is enabled.
In the case of a device that wirelessly transmits an image signal, also, when a secure connection is established using HDMI, etc., between a source device, such as a recording and reproducing apparatus, and a wireless device (data transmitting apparatus) and between a wireless device (data receiving apparatus) and a sink device such as a display, the devices can mutually determine whether they are authorized devices, by using security information stored in each device. Consequently, allowance for signal transmission between differing transmitting and receiving devices is enabled.    [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-37591    [Patent Document 2] Japanese Patent Application Laid-Open No. 2006-128963